/*
 * XILINX CDMA Engine test module
 *
 * Copyright (C) 2012 Xilinx, Inc. All rights reserved.
 *
 * Based on Atmel DMA Test Client
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/init.h>
#include <linux/kthread.h>
#include <linux/module.h>
#include <linux/random.h>
#include <linux/slab.h>
#include <linux/of_dma.h>
#include <linux/platform_device.h>
#include <linux/wait.h>
#include <linux/dma/xilinx_dma.h>

static unsigned int test_buf_size = 64;
module_param(test_buf_size, uint, S_IRUGO);
MODULE_PARM_DESC(test_buf_size, "Size of the memcpy test buffer");

static char test_channel[20];
module_param_string(channel, test_channel, sizeof(test_channel), S_IRUGO);
MODULE_PARM_DESC(channel, "Bus ID of the channel to test (default: any)");

static char test_device[20];
module_param_string(device, test_device, sizeof(test_device), S_IRUGO);
MODULE_PARM_DESC(device, "Bus ID of the DMA Engine to test (default: any)");

static unsigned int threads_per_chan = 1;
module_param(threads_per_chan, uint, S_IRUGO);
MODULE_PARM_DESC(threads_per_chan,
                "Number of threads to start per channel (default: 1)");

static unsigned int max_channels;
module_param(max_channels, uint, S_IRUGO);
MODULE_PARM_DESC(max_channels,
                "Maximum number of channels to use (default: all)");

static unsigned int iterations = 5;
module_param(iterations, uint, S_IRUGO);
MODULE_PARM_DESC(iterations,
                "Iterations before stopping test (default: infinite)");

static unsigned int xor_sources = 3;
module_param(xor_sources, uint, S_IRUGO);
MODULE_PARM_DESC(xor_sources,
                "Number of xor source buffers (default: 3)");

static unsigned int pq_sources = 3;
module_param(pq_sources, uint, S_IRUGO);
MODULE_PARM_DESC(pq_sources,
                "Number of p+q source buffers (default: 3)");

/*
 * Initialization patterns. All bytes in the source buffer has bit 7
 * set, all bytes in the destination buffer has bit 7 cleared.
 *
 * Bit 6 is set for all bytes which are to be copied by the DMA
 * engine. Bit 5 is set for all bytes which are to be overwritten by
 * the DMA engine.
 *
 * The remaining bits are the inverse of a counter which increments by
 * one for each byte address.
 */
#define PATTERN_SRC             0x80
#define PATTERN_DST             0x00
#define PATTERN_COPY            0x40
#define PATTERN_OVERWRITE       0x20
#define PATTERN_COUNT_MASK      0x1f

struct cdmatest_thread {
        struct list_head node;
        struct task_struct *task;
        struct dma_chan *chan;
        u8 **srcs;
        u8 **dsts;
        enum dma_transaction_type type;
        bool done;
};

struct cdmatest_chan {
        struct list_head node;
        struct dma_chan *chan;
        struct list_head threads;
};

/*
 * These are protected by dma_list_mutex since they're only used by
 * the DMA filter function callback
 */
static DECLARE_WAIT_QUEUE_HEAD(thread_wait);
static LIST_HEAD(cdmatest_channels);
static unsigned int nr_channels;

static bool is_threaded_test_run(struct cdmatest_chan *tx_dtc)
{
        struct cdmatest_thread *thread;

        list_for_each_entry(thread, &tx_dtc->threads, node) {
                if (!thread->done)
                        return true;
        }

        return false;
}

static unsigned long cdmatest_random(void)
{
        unsigned long buf;

        get_random_bytes(&buf, sizeof(buf));
        return buf;
}

static void cdmatest_init_srcs(u8 **bufs, unsigned int start, unsigned int len)
{
        unsigned int i;
        u8 *buf;

        for (; (buf = *bufs); bufs++) {
                for (i = 0; i < start; i++)
                        buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
                for ( ; i < start + len; i++)
                        buf[i] = PATTERN_SRC | PATTERN_COPY
                                | (~i & PATTERN_COUNT_MASK);
                for ( ; i < test_buf_size; i++)
                        buf[i] = PATTERN_SRC | (~i & PATTERN_COUNT_MASK);
                buf++;
        }
}

static void cdmatest_init_dsts(u8 **bufs, unsigned int start, unsigned int len)
{
        unsigned int i;
        u8 *buf;

        for (; (buf = *bufs); bufs++) {
                for (i = 0; i < start; i++)
                        buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
                for ( ; i < start + len; i++)
                        buf[i] = PATTERN_DST | PATTERN_OVERWRITE
                                | (~i & PATTERN_COUNT_MASK);
                for ( ; i < test_buf_size; i++)
                        buf[i] = PATTERN_DST | (~i & PATTERN_COUNT_MASK);
        }
}

static void cdmatest_mismatch(u8 actual, u8 pattern, unsigned int index,
                unsigned int counter, bool is_srcbuf)
{
        u8 diff = actual ^ pattern;
        u8 expected = pattern | (~counter & PATTERN_COUNT_MASK);
        const char *thread_name = current->comm;

        if (is_srcbuf)
                pr_warn(
                "%s: srcbuf[0x%x] overwritten! Expected %02x, got %02x\n",
                                thread_name, index, expected, actual);
        else if ((pattern & PATTERN_COPY)
                        && (diff & (PATTERN_COPY | PATTERN_OVERWRITE)))
                pr_warn(
                "%s: dstbuf[0x%x] not copied! Expected %02x, got %02x\n",
                                thread_name, index, expected, actual);
        else if (diff & PATTERN_SRC)
                pr_warn(
                "%s: dstbuf[0x%x] was copied! Expected %02x, got %02x\n",
                                thread_name, index, expected, actual);
        else
                pr_warn(
                "%s: dstbuf[0x%x] mismatch! Expected %02x, got %02x\n",
                                thread_name, index, expected, actual);
}

static unsigned int cdmatest_verify(u8 **bufs, unsigned int start,
                unsigned int end, unsigned int counter, u8 pattern,
                bool is_srcbuf)
{
        unsigned int i;
        unsigned int error_count = 0;
        u8 actual;
        u8 expected;
        u8 *buf;
        unsigned int counter_orig = counter;

        for (; (buf = *bufs); bufs++) {
                counter = counter_orig;
                for (i = start; i < end; i++) {
                        actual = buf[i];
                        expected = pattern | (~counter & PATTERN_COUNT_MASK);
                        if (actual != expected) {
                                if (error_count < 32)
                                        cdmatest_mismatch(actual, pattern, i,
                                                        counter, is_srcbuf);
                                error_count++;
                        }
                        counter++;
                }
        }

        if (error_count > 32)
                pr_warn("%s: %u errors suppressed\n",
                        current->comm, error_count - 32);

        return error_count;
}

static void cdmatest_callback(void *completion)
{
        complete(completion);
}

/*
 * This function repeatedly tests DMA transfers of various lengths and
 * offsets for a given operation type until it is told to exit by
 * kthread_stop(). There may be multiple threads running this function
 * in parallel for a single channel, and there may be multiple channels
 * being tested in parallel.
 *
 * Before each test, the source and destination buffer is initialized
 * with a known pattern. This pattern is different depending on
 * whether it's in an area which is supposed to be copied or
 * overwritten, and different in the source and destination buffers.
 * So if the DMA engine doesn't copy exactly what we tell it to copy,
 * we'll notice.
 */
static int cdmatest_func(void *data)
{
        struct cdmatest_thread *thread = data;
        struct dma_chan *chan;
        const char *thread_name;
        unsigned int src_off, dst_off, len;
        unsigned int error_count;
        unsigned int failed_tests = 0;
        unsigned int total_tests = 0;
        dma_cookie_t cookie;
        enum dma_status status;
        enum dma_ctrl_flags flags;
        u8 pq_coefs[pq_sources + 1];
        int ret;
        int src_cnt;
        int dst_cnt;
        int i;

        thread_name = current->comm;

        ret = -ENOMEM;

        /* JZ: limit testing scope here */

        smp_rmb();
        chan = thread->chan;
        if (thread->type == DMA_MEMCPY)
                src_cnt = dst_cnt = 1;
        else if (thread->type == DMA_XOR) {
                src_cnt = xor_sources | 1;
                                /* force odd to ensure dst = src */
                dst_cnt = 1;
        } else if (thread->type == DMA_PQ) {
                src_cnt = pq_sources | 1;
                                /* force odd to ensure dst = src */
                dst_cnt = 2;
                for (i = 0; i < src_cnt; i++)
                        pq_coefs[i] = 1;
        } else
                goto err_srcs;

        thread->srcs = kcalloc(src_cnt+1, sizeof(u8 *), GFP_KERNEL);
        if (!thread->srcs)
                goto err_srcs;
        for (i = 0; i < src_cnt; i++) {
                thread->srcs[i] = kmalloc(test_buf_size, GFP_KERNEL);
                if (!thread->srcs[i])
                        goto err_srcbuf;
        }
        thread->srcs[i] = NULL;

        thread->dsts = kcalloc(dst_cnt+1, sizeof(u8 *), GFP_KERNEL);
        if (!thread->dsts)
                goto err_dsts;
        for (i = 0; i < dst_cnt; i++) {
                thread->dsts[i] = kmalloc(test_buf_size, GFP_KERNEL);
                if (!thread->dsts[i])
                        goto err_dstbuf;
        }
        thread->dsts[i] = NULL;

        set_user_nice(current, 10);

        flags = DMA_CTRL_ACK | DMA_PREP_INTERRUPT;

        while (!kthread_should_stop()
                && !(iterations && total_tests >= iterations)) {
                struct dma_device *dev = chan->device;
                struct dma_async_tx_descriptor *tx = NULL;
                dma_addr_t dma_srcs[src_cnt];
                dma_addr_t dma_dsts[dst_cnt];
                struct completion cmp;
                unsigned long tmo = msecs_to_jiffies(3000);
                u8 align = 0;

                total_tests++;

                /* honor alignment restrictions */
                if (thread->type == DMA_MEMCPY)
                        align = dev->copy_align;
                else if (thread->type == DMA_XOR)
                        align = dev->xor_align;
                else if (thread->type == DMA_PQ)
                        align = dev->pq_align;

                if (1 << align > test_buf_size) {
                        pr_err("%u-byte buffer too small for %d-byte alignment\n",
                               test_buf_size, 1 << align);
                        break;
                }

                len = cdmatest_random() % test_buf_size + 1;
                len = (len >> align) << align;
                if (!len)
                        len = 1 << align;
                src_off = cdmatest_random() % (test_buf_size - len + 1);
                dst_off = cdmatest_random() % (test_buf_size - len + 1);

                src_off = (src_off >> align) << align;
                dst_off = (dst_off >> align) << align;

                cdmatest_init_srcs(thread->srcs, src_off, len);
                cdmatest_init_dsts(thread->dsts, dst_off, len);

                for (i = 0; i < src_cnt; i++) {
                        u8 *buf = thread->srcs[i] + src_off;

                        dma_srcs[i] = dma_map_single(dev->dev, buf, len,
                                                        DMA_MEM_TO_DEV);
                }
                /* map with DMA_MEM_TO_MEM to force writeback/invalidate */
                for (i = 0; i < dst_cnt; i++) {
                        dma_dsts[i] = dma_map_single(dev->dev, thread->dsts[i],
                                                        test_buf_size,
                                                        DMA_MEM_TO_MEM);
                }

                if (thread->type == DMA_MEMCPY) {
                        tx = dev->device_prep_dma_memcpy(chan,
                                                        dma_dsts[0] + dst_off,
                                                        dma_srcs[0], len,
                                                        flags);

                } else if (thread->type == DMA_XOR)
                        tx = dev->device_prep_dma_xor(chan,
                                                        dma_dsts[0] + dst_off,
                                                        dma_srcs, src_cnt,
                                                        len, flags);
                else if (thread->type == DMA_PQ) {
                        dma_addr_t dma_pq[dst_cnt];

                        for (i = 0; i < dst_cnt; i++)
                                dma_pq[i] = dma_dsts[i] + dst_off;
                        tx = dev->device_prep_dma_pq(chan, dma_pq, dma_srcs,
                                                        src_cnt, pq_coefs,
                                                        len, flags);
                }

                if (!tx) {
                        for (i = 0; i < src_cnt; i++)
                                dma_unmap_single(dev->dev, dma_srcs[i], len,
                                                        DMA_MEM_TO_DEV);
                        for (i = 0; i < dst_cnt; i++)
                                dma_unmap_single(dev->dev, dma_dsts[i],
                                                        test_buf_size,
                                                        DMA_MEM_TO_MEM);
                        pr_warn(
                        "%s: #%u: prep error with src_off=0x%x ",
                                thread_name, total_tests - 1, src_off);
                        pr_warn("dst_off=0x%x len=0x%x\n",
                                        dst_off, len);
                        msleep(100);
                        failed_tests++;
                        continue;
                }

                init_completion(&cmp);
                tx->callback = cdmatest_callback;
                tx->callback_param = &cmp;
                cookie = tx->tx_submit(tx);

                if (dma_submit_error(cookie)) {
                        pr_warn(
                        "%s: #%u: submit error %d with src_off=0x%x ",
                                        thread_name, total_tests - 1,
                                        cookie, src_off);
                        pr_warn("dst_off=0x%x len=0x%x\n",
                                        dst_off, len);
                        msleep(100);
                        failed_tests++;
                        continue;
                }
                dma_async_issue_pending(chan);

                tmo = wait_for_completion_timeout(&cmp, tmo);
                status = dma_async_is_tx_complete(chan, cookie, NULL, NULL);

                if (tmo == 0) {
                        pr_warn("%s: #%u: test timed out\n",
                                        thread_name, total_tests - 1);
                        failed_tests++;
                        continue;
                } else if (status != DMA_COMPLETE) {
                        pr_warn(
                        "%s: #%u: got completion callback, ",
                                        thread_name, total_tests - 1);
                        pr_warn("but status is \'%s\'\n",
                                        status == DMA_ERROR ? "error" :
                                                        "in progress");
                        failed_tests++;
                        continue;
                }

                /* Unmap by myself */
                for (i = 0; i < dst_cnt; i++)
                        dma_unmap_single(dev->dev, dma_dsts[i], test_buf_size,
                                        DMA_MEM_TO_MEM);

                error_count = 0;

                pr_debug("%s: verifying source buffer...\n", thread_name);
                error_count += cdmatest_verify(thread->srcs, 0, src_off,
                                0, PATTERN_SRC, true);
                error_count += cdmatest_verify(thread->srcs, src_off,
                                src_off + len, src_off,
                                PATTERN_SRC | PATTERN_COPY, true);
                error_count += cdmatest_verify(thread->srcs, src_off + len,
                                test_buf_size, src_off + len,
                                PATTERN_SRC, true);

                pr_debug("%s: verifying dest buffer...\n",
                                thread->task->comm);
                error_count += cdmatest_verify(thread->dsts, 0, dst_off,
                                0, PATTERN_DST, false);
                error_count += cdmatest_verify(thread->dsts, dst_off,
                                dst_off + len, src_off,
                                PATTERN_SRC | PATTERN_COPY, false);
                error_count += cdmatest_verify(thread->dsts, dst_off + len,
                                test_buf_size, dst_off + len,
                                PATTERN_DST, false);

                if (error_count) {
                        pr_warn("%s: #%u: %u errors with ",
                                thread_name, total_tests - 1, error_count);
                        pr_warn("src_off=0x%x dst_off=0x%x len=0x%x\n",
                                src_off, dst_off, len);
                        failed_tests++;
                } else {
                        pr_debug("%s: #%u: No errors with ",
                                thread_name, total_tests - 1);
                        pr_debug("src_off=0x%x dst_off=0x%x len=0x%x\n",
                                src_off, dst_off, len);
                }
        }

        ret = 0;
        for (i = 0; thread->dsts[i]; i++)
                kfree(thread->dsts[i]);
err_dstbuf:
        kfree(thread->dsts);
err_dsts:
        for (i = 0; thread->srcs[i]; i++)
                kfree(thread->srcs[i]);
err_srcbuf:
        kfree(thread->srcs);
err_srcs:
        pr_notice("%s: terminating after %u tests, %u failures (status %d)\n",
                        thread_name, total_tests, failed_tests, ret);

        thread->done = true;
        wake_up(&thread_wait);

        return ret;
}

static void cdmatest_cleanup_channel(struct cdmatest_chan *dtc)
{
        struct cdmatest_thread *thread;
        struct cdmatest_thread *_thread;
        int ret;

        list_for_each_entry_safe(thread, _thread, &dtc->threads, node) {
                ret = kthread_stop(thread->task);
                pr_debug("cdmatest: thread %s exited with status %d\n",
                                thread->task->comm, ret);
                list_del(&thread->node);
                put_task_struct(thread->task);
                kfree(thread);
        }
        kfree(dtc);
}

static int cdmatest_add_threads(struct cdmatest_chan *dtc,
                                enum dma_transaction_type type)
{
        struct cdmatest_thread *thread;
        struct dma_chan *chan = dtc->chan;
        char *op;
        unsigned int i;

        if (type == DMA_MEMCPY)
                op = "copy";
        else if (type == DMA_XOR)
                op = "xor";
        else if (type == DMA_PQ)
                op = "pq";
        else
                return -EINVAL;

        for (i = 0; i < threads_per_chan; i++) {
                thread = kzalloc(sizeof(struct cdmatest_thread), GFP_KERNEL);
                if (!thread) {
                        pr_warn("cdmatest: No memory for %s-%s%u\n",
                                        dma_chan_name(chan), op, i);

                        break;
                }
                thread->chan = dtc->chan;
                thread->type = type;
                smp_wmb();
                thread->task = kthread_run(cdmatest_func, thread, "%s-%s%u",
                                dma_chan_name(chan), op, i);
                if (IS_ERR(thread->task)) {
                        pr_warn("cdmatest: Failed to run thread %s-%s%u\n",
                                        dma_chan_name(chan), op, i);
                        kfree(thread);
                        break;
                }

                /* srcbuf and dstbuf are allocated by the thread itself */
                get_task_struct(thread->task);
                list_add_tail(&thread->node, &dtc->threads);
        }

        return i;
}

static int cdmatest_add_channel(struct dma_chan *chan)
{
        struct cdmatest_chan *dtc;
        struct dma_device *dma_dev = chan->device;
        unsigned int thread_count = 0;
        int cnt;

        dtc = kmalloc(sizeof(struct cdmatest_chan), GFP_KERNEL);
        if (!dtc) {
                pr_warn("cdmatest: No memory for %s\n", dma_chan_name(chan));
                return -ENOMEM;
        }

        dtc->chan = chan;
        INIT_LIST_HEAD(&dtc->threads);

        if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) {
                cnt = cdmatest_add_threads(dtc, DMA_MEMCPY);
                thread_count += cnt > 0 ? cnt : 0;
        }
        if (dma_has_cap(DMA_XOR, dma_dev->cap_mask)) {
                cnt = cdmatest_add_threads(dtc, DMA_XOR);
                thread_count += cnt > 0 ? cnt : 0;
        }
        if (dma_has_cap(DMA_PQ, dma_dev->cap_mask)) {
                cnt = cdmatest_add_threads(dtc, DMA_PQ);
                thread_count += cnt > 0 ? cnt : 0;
        }

        pr_info("cdmatest: Started %u threads using %s\n",
                thread_count, dma_chan_name(chan));

        list_add_tail(&dtc->node, &cdmatest_channels);
        nr_channels++;

        if (iterations)
                wait_event(thread_wait, !is_threaded_test_run(dtc));

        return 0;
}

static int xilinx_cdmatest_probe(struct platform_device *pdev)
{
        struct dma_chan *chan;
        int err;

        chan = dma_request_slave_channel(&pdev->dev, "cdma");
        if (IS_ERR(chan)) {
                pr_err("xilinx_cdmatest: No channel\n");
                return PTR_ERR(chan);
        }

        err = cdmatest_add_channel(chan);
        if (err) {
                pr_err("xilinx_cdmatest: Unable to add channel\n");
                goto free_tx;
        }
        return 0;

free_tx:
        dma_release_channel(chan);

        return err;
}

static int xilinx_cdmatest_remove(struct platform_device *pdev)
{
        struct cdmatest_chan *dtc, *_dtc;
        struct dma_chan *chan;

        list_for_each_entry_safe(dtc, _dtc, &cdmatest_channels, node) {
                list_del(&dtc->node);
                chan = dtc->chan;
                cdmatest_cleanup_channel(dtc);
                pr_info("xilinx_cdmatest: dropped channel %s\n",
                        dma_chan_name(chan));
                dma_release_channel(chan);
        }
        return 0;
}

static const struct of_device_id xilinx_cdmatest_of_ids[] = {
        { .compatible = "xlnx,axi-cdma-test-1.00.a", },
        {}
};

static struct platform_driver xilinx_cdmatest_driver = {
        .driver = {
                .name = "xilinx_cdmatest",
                .owner = THIS_MODULE,
                .of_match_table = xilinx_cdmatest_of_ids,
        },
        .probe = xilinx_cdmatest_probe,
        .remove = xilinx_cdmatest_remove,
};

static int __init cdma_init(void)
{
        return platform_driver_register(&xilinx_cdmatest_driver);

}
late_initcall(cdma_init);

static void __exit cdma_exit(void)
{
        platform_driver_unregister(&xilinx_cdmatest_driver);
}
module_exit(cdma_exit)

MODULE_AUTHOR("Xilinx, Inc.");
MODULE_DESCRIPTION("Xilinx AXI CDMA Test Client");
MODULE_LICENSE("GPL v2");